The Body’s Defenses The lymphatic System

Functions of Lymphatic System Help protect body from infection by disease causing agents Must detect a wide variety of agents, known as pathogens, from viruses to parasitic worms, and distinguish them from the organism's own healthy tissue.

Antigen: proteins that body recognizes as foreign (pathogens, foreign cells, or cancer cells)

The boy in a bubble David Vetter

How does the body combat disease?

Specific immunity Specific Immunity aka: acquired immunity Direct contact with antigens and intimate a response that marks and destroys antigens

Non-specific Immunity NON-specific immunity (innate immunity) cells of the innate system recognize and respond to pathogens in a generic way, but, unlike the adaptive immune system (which is found only in vertebrates), it does not confer long-lasting or protective immunity to the host

Body’s Defenses: concept map Specific Cell Mediated immunity T cells Humoral immunity B cells which stimulate Ab production from plasma cells Antibodies: proteins capable of interactive with antigens Non-specific Mechanical Barriers Mucous membranes, GI, eyes, Respiratory system, and skin WBC Neutrophils Natural killer cell monocytes Lymphocytes Eosinophils basophils Inflammatory responses Histamine reactions chemical factors released by injured cells and serves to establish a physical barrier against the spread of infection, and to promote healing of any damaged tissue following the clearance of pathogens

Blood Cells: Leukocytes White Blood Cells Approximately 5,000 to 9,000 per cubic mm of blood Defends body from pathogens Divided into two types Granular Leukocytes Nongranular Leukocytes

Granular Leukocytes Neutrophils Phagocyte; 1 st to arrive at injury site Releases chemicals to degrade pathogen and attract other phagocytes Hallmark of ACUTE infections 50-70% of WBC’s Nucleus is segmented into 4-5 lobes

Granular Leukocytes Eosinophils Phagocytes of antibody marked pathogens Mediate for allergies Reduces inflammation Defend against large parasites Strong chemotaxis Attraction to injury and infection 2-4% of WBC’s Nucleus is segmented into 2 lobes Red Granules

Granular Leukocytes Basophils Functions in allergic response by releasing histamine Secretes heparin Anticoagulant Rare, less than 1% Deep blue granules Difficult to see nucleus

Nongranular Leukocytes Lymphocytes Part of acquired immune response… specific defense against bacteria and viruses Forms different types of cells: T-Cells: destroys foreign cells B-Cells: differentiate into plasma cells which secrete specific antibodies NK Cells: prevent cancer 20-30% of WBC’s Large round nucleus

Nongranular Leukocytes Monocytes Phagocytes Scavengers Fixed vs. Free Releases chemicals to attract other WBCs and fibroblasts (scar tissue) 2-8% of WBC Large, kidney bean shaped nucleus

White Blood Cell Disorders Leukopenia Low WBC (> 5,000 mm 3 ) May accompany: May accompany: Typhoid fever, Flu, Chicken Pox, AIDS Typhoid fever, Flu, Chicken Pox, AIDS Leukocytosis High WBC Indicates acute infection Leukemia Extremely high WBC Malignant

Practice Identifying Leukocytes View following cells for practice

WBC: Matching Match the cell types with the descriptions and microscope images

Neutrophils 40-70% Phagocytizes primarily bacteria

Eosinophils 1-4% Phaocytizes and destroys antigen- antibody complexes

Basophils 0-1% Releases histamine when stimulated

Lymphocytes 20-45% B type produces antibodies in blood and lymp; T types kills virus containing cells

Monocyte 4-8% Becomes macrophage- phagocytizes bacteria and viruses

Exit Slip: turn in as you leave 1.Pretend your friend was absent from class today. She/he asks you to explain the lesson. On your own paper, tell him/her about your lesson today. Be sure to relate to the learning target. 2.Include one new thing you learned. 3.Share something that you would like me to go over in class tomorrow to help you learn material/concept better.